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Bader, E. R.

Publications and source records attributed to Bader, E. R..

2 recordsLinked to original sources

Electrical stimulation of the human pulvinar generates visual percepts

Visual prostheses have targeted early structures in the visual pathway, including the retina, optic nerve, lateral geniculate nucleus, and visual cortex, to generate visual percepts. Stimulation of higher-order visual regions, which may better encode complex visual features, remains relatively unexplored. We tested whether electrical stimulation of the medial and inferior pulvinar elicits visual percepts in a patient with medically refractory epilepsy undergoing invasive seizure monitoring with intracranial electroencephalography. Bipolar stimulation (30 biphasic pulses, 0.5 ms per phase, 3 mA, 1 Hz) was delivered between adjacent pulvinar contacts while eye movements were tracked. Stimulation of different electrode pairs elicited visual percepts at distinct retinotopic locations (p = 0.010). Stimulation also altered cortical activity, producing an early power increase followed by gamma desynchronization in occipital and parietal regions (p < 0.001) and beta desynchronization in the lateral temporal region (p < 0.01). These findings suggest that pulvinar stimulation can generate visual percepts and modulate distributed cortical networks, supporting further investigation of the pulvinar as a target for vision restoration.

neuroscience↗

An in vivo platform for rebuilding functional neocortical tissue

Recent progress in cortical stem cell transplantation has demonstrated its potential to repair the brain. However, current transplant models have yet to demonstrate that the circuitry of transplant-derived neurons can encode useful function to the host. This is likely due to missing cell types within the grafts, abnormal proportions of cell types, abnormal cytoarchitecture, and inefficient vascularization. Here, we devised a transplant platform for testing neocortical tissue prototypes. Dissociated mouse embryonic telencephalic cells in a liquid scaffold were transplanted into aspiration-lesioned adult mouse cortices. The donor neuronal precursors differentiated into upper and deep layer neurons that exhibited synaptic puncta, projected outside of the graft to appropriate brain areas, became electrophysiologically active within one month post-transplant, and responded to visual stimuli. Interneurons and oligodendrocytes were present at normal densities in grafts. Grafts became fully vascularized by 1-week post-transplant and vessels in grafts were perfused with blood. With this paradigm, we could also organize cells into layers. Overall, we have provided proof of concept for an in vivo platform that can be used for developing and testing neocortical-like tissue prototypes.

neuroscience↗